Asaphida

Ampyxinella rotundata

Order Asaphida / Superfamily Trinucleoidea / Family Raphiophoridae

Katian (Late Ordovician)Xinjiang

Ampyxinella rotundata — photo 1 — Photo 1 · Holotype (Xinjiang; Zhang Wentang Holotype of "A. ovata" (Xinjiang; Zhang Wentang Holotype of "A. circulare" (Xinjiang; Zhang Tairong 1979) 1979) 1981) Literature specimen (Xinjiang; Zhou et al., (Xinjiang; Lixia) (Xinjiang; Baishui) 1995)

Ampyxinella rotundata — photo 2 — Photo 2 · Holotype (Xinjiang; Zhang Wentang Holotype of "A. ovata" (Xinjiang; Zhang Wentang Holotype of "A. circulare" (Xinjiang; Zhang Tairong 1979) 1979) 1981) Literature specimen (Xinjiang; Zhou et al., (Xinjiang; Lixia) (Xinjiang; Baishui) 1995)

Ampyxinella rotundata — photo 3 — Photo 3 · Holotype (Xinjiang; Zhang Wentang Holotype of "A. ovata" (Xinjiang; Zhang Wentang Holotype of "A. circulare" (Xinjiang; Zhang Tairong 1979) 1979) 1981) Literature specimen (Xinjiang; Zhou et al., (Xinjiang; Lixia) (Xinjiang; Baishui) 1995)

Ampyxinella rotundata — photo 4 — Photo 4 · Holotype (Xinjiang; Zhang Wentang Holotype of "A. ovata" (Xinjiang; Zhang Wentang Holotype of "A. circulare" (Xinjiang; Zhang Tairong 1979) 1979) 1981) Literature specimen (Xinjiang; Zhou et al., (Xinjiang; Lixia) (Xinjiang; Baishui) 1995)

Ampyxinella rotundata — photo 5 — Photo 5 · Holotype (Xinjiang; Zhang Wentang Holotype of "A. ovata" (Xinjiang; Zhang Wentang Holotype of "A. circulare" (Xinjiang; Zhang Tairong 1979) 1979) 1981) Literature specimen (Xinjiang; Zhou et al., (Xinjiang; Lixia) (Xinjiang; Baishui) 1995)

Ampyxinella rotundata — photo 6 — Photo 6 · Holotype (Xinjiang; Zhang Wentang Holotype of "A. ovata" (Xinjiang; Zhang Wentang Holotype of "A. circulare" (Xinjiang; Zhang Tairong 1979) 1979) 1981) Literature specimen (Xinjiang; Zhou et al., (Xinjiang; Lixia) (Xinjiang; Baishui) 1995)

Ampyxinella rotundata — photo 7 — Photo 7 · Holotype (Xinjiang; Zhang Wentang Holotype of "A. ovata" (Xinjiang; Zhang Wentang Holotype of "A. circulare" (Xinjiang; Zhang Tairong 1979) 1979) 1981) Literature specimen (Xinjiang; Zhou et al., (Xinjiang; Lixia) (Xinjiang; Baishui) 1995)

Classification

Order Asaphida / Superfamily Trinucleoidea / Family Raphiophoridae

Genus

Ampyxinella Koroleva, 1959

Genus author

Koroleva M. N.

Genus etymology

ampyxin-, Ampyxina, a trilobite genus name; -ella, a diminutive suffix

Species

A. rotundata Zhang, 1979

Species author

Zhang Wentang

Species etymology

rotundata, rounded

Age

Katian (Late Ordovician)

Distribution

Xinjiang

Synonyms

Ampyxinella ovata; Ampyxinella circulare

Diagnosis

Dorsal shield circular, cephalon or whole body covered with terrace lines. Cephalon semicircular; glabella convex, pear-shaped, with V-shaped terrace ridges, lateral lobes convex; occipital ring narrow; eye tubercles distinct. Thorax of 6 segments, axis narrow; first segment longitudinally somewhat longer, first axial ring with a pair of wide, deep, short, oblique furrows at the anterior lateral sides, pleural furrows narrow. Pygidium short, slightly triangular; axis sharp-conical, with ~10 axial rings; 4 pairs of pleural furrows; border narrow laterally, wide medially and slightly concave behind the axis.

Remarks

Zhou et al. (1995) concluded that this species mainly shows three intraspecific forms, differing in the width-length ratios of the cranidium and glabella, the thoracic axial width, and the type of surface terrace-line ornament.